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Expired Canadian patentCanada

Method and apparatus for mixing chemicals into fiber pulp

CA 1307416 C · Owner: Frisk, Per-Olof · Inventors: Frisk, Per-Olof; Lindahl, Arne; Frisk, Edvin

CIPO record

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

In a method and an apparatus for mixing chemicals into a fibre pulp, the pulp passes in a space between a fixed casing and a rotating device through three treatment sections. In the first treatment section a transport screw is arranged for transporting the pulp and impart to it a pressure up to the subsequent treatment section. In this treatment section both the casing and the rotating device are provided with guide elements which cause shearing between the fibre layers of the pulp by alternating velocity gradiants in the pulp and oscillating movement thereof. In the next treatment section the pulp is imparted a retarding velocity in a first part of the section and thereafter an …

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted September 15, 1992. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 15, 2009.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 17, 1987
GrantedSeptember 15, 1992
Term endedSeptember 15, 2009
Patent numberCA 1307416 C
Classification (IPC)B02C19/22 +2 more

Timeline

Timeline From CIPO dates

19881991199419972000200320062009Application filedNov 17, 1987Patent grantedSep 15, 1992Term endedSep 15, 2009

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.